Leading shipwreck hunter David Mearns is one of the 30 crew who will board SV Geosounder to search for the wreck.

The Finding Sydney Foundation has raised $5 million to mount the operation, which will allow the search to go on until the end of April.

Finding Sydney project manager Patrick Flynn said the search area had been defined by close examination of historical records.

"That led to the northern area,'' Mr Flynn said.

"As well as what we've been doing over the last month, a fairly meteorological review of the actual weather patterns that occurred on that day, and you use a thing called hindcasting (testing a theoretical model).''

Royal Australian Navy historian Lieutenant John Perryman said there was a high degree of confidence the search area would result in success.

"That has bought us to where we are at the moment, which is on doorstop of an historic voyage of discovery and hopefully commemoration,'' Lieutenant Perryman said.

But there were split feelings among researchers about the wreck's whereabouts, Lieutenant Perryman said.

"I'm aware that there are detractors out there who have made remarks about looking in the wrong spot, this being a waste of taxpayers money, but there's nothing that I can say that will alter their deeply and long held views,'' he said.

"I think we're probably going to come up trumps.''

The search will focus on identifying the resting place of the Kormoran before turning its sights to the Sydney.

"It's certainly our intention if we find either or both wrecks we will be commemorating those crews and having a short service on behalf of the relatives of both the German and Australian crews,'' Lieutenant Perryman said.

The loss of the Sydney often overshadowed the sacrifice the sailors made for Australia, he said.

"They removed a deadly and very, very lethal threat from Australia's wartime sea lines of communication,'' he said.

"Had Kormoran continued to roam the Indian Ocean, she could have caused untold damage to the troop ships.

"I think that sometimes the loss of the entire crew overshadows the fact, their sacrifice wasn't in vain.

"To the last there was evidence that these people remained at their post, they fought to the end and then they fought to save their ship right up until the last.''